patch 9.1.0849: there are a few typos in the source

Problem:  there are a few typos in the source.
Solution: Correct typos (zeertzjq).

closes: #16026

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_diffmode.vim b/src/testdir/test_diffmode.vim
index a654b6d..bed795e 100644
--- a/src/testdir/test_diffmode.vim
+++ b/src/testdir/test_diffmode.vim
Binary files differ